I have the same problem with sleeping in over-the-ear headsets. The best I've found for sleeping on long flights are the Bose QC20 - the noise cancelling is as

I have the same problem with sleeping in over-the-ear headsets. The best I've found for sleeping on long flights are the Bose QC20 - the noise cancelling is as good as their over-the-ear headsets but the in-ear design makes them much more comfortable if you happen to rest your head on one side while sleeping, and doing so doesn't interrupt the noise cancellation. Since they're cabled to an external battery box they can easily last through any flight, and you can leave the USB charge cable connected to an in-flight power socket while you use them to keep the battery full.